Enhancing images in scattering media utilizing stereovision and polarization

Consider photography in scattering media. One goal is to enhance the images and compensate for scattering effects. A second goal is to estimate a distance map of the scene. A prior method exists to achieve these goals. It is based on acquiring two images from a fixed position, using a single camera mounted with a polarizer at different settings. However, the shortcomings of this polarization-based method comprise having to acquire these images sequentially, reduced light level, and inapplicability at low backscatter degree of polarization. In this paper, a new technique is described to alleviate these issues by integrating polarization and stereo cues. More precisely, the earlier single-camera method is extended to a pair of cameras displaced by a finite baseline. Each camera utilizes polarizers at different settings. Stereo disparity and polarization analysis are fused to construct de-scattered left and right views. The binocular stereo cues provide additional geometric constraints for distance computation. Moreover, the proposed technique acquires the two raw images simultaneously. Thus it can be applied to dynamic scenes. Underwater experiments are presented.